(200b) Elasticity Of Single Poly(Ethylene Oxide) Molecule In Water And Hexadecane

Understanding the elastic behavior of single polymer chains in solutions is important as a basic problem in rubber elasticity, and as a practical problem in many industries. This work reports results from molecular dynamics (umbrella sampling) studies of stretching a single poly(ethylene oxide) (PEO) chain in water and hexadecane solutions, and compares with experimental determinations. Excellent agreement was found betweeen simulated forces as a function of PEO chain extension and atomic force microscopy measurements. To eluciate the molecular origins of the different elastic behavior of the amphiphilic PEO chain in water and hexadecane, we investigated the helicity of the PEO chain and the number of water bridges as a function of the chain extension. In addition, we also analyzed the role of the intrinsic hydrophobicity of the PEO monomer and the effect of temperature on the elastic behavior of PEO in water and hexadecane.